Evaluation of bearing capacity envelope of mat foundations in soft clay seabed under wave loads using kriging-based response surface method

Abstract

This study examines the influence of cyclic wave loads on the bearing capacity envelope of mat foundations for bottom-supported platforms in saturated soft clay seabed. These platforms offer advantages in terms of quick installation and removal but may experience reduced bearing capacity due to cyclic wave loads. An evaluation method for the failure envelope of mat foundation using Kriging-based response surface methodology under wave action is proposed. To achieve this, we incorporated an elastoplastic constitutive model for cyclic loading into the ABAQUS finite element method platform, utilizing a self-compiled user-defined material (UMAT) code to describe clay behavior. The evolution of uniaxial bearing capacity and vertical-horizontal-moment (VHM) bearing capacity failure envelope are investigated. The performances of Kriging-based response surface methodology and original response surface methodology are compared, and the evaluation of the VHM failure envelope using the Kriging-based response surface methodology is presented. Results indicate that cyclic wave loads can cause significant weakening of the initial bearing capacity failure envelopes of mat foundations. However, it is worth noting that cyclic wave loads only affect the magnitude of the envelope surface and not its shape. Furthermore, the bearing capacity failure envelope of mat foundations decreases with increasing cyclic stress ratio, frequency, and time factor of cyclic wave loads. The evaluation method for the failure envelope of mat foundation bearing capacity based on Kriging-based response surface methodology under the action of wave loads outperforms the original response surface methodology and can serve as a valuable reference for engineering design.